Many therapeutic proteins such as, for example, antibodies require administration by injection or infusion via the intravenous route. The amount of protein that can be administered intravenously is limited by solubility and stability of the protein in a suitable liquid composition and by the volume of the infusion fluid. An alternative administration pathway is subcutaneous injection. This injection pathway requires a high protein concentration in the final solution to be injected (Shire et al., Journal of Pharmaceutical Science, 2004; 93(6): 1390-1402; Roskos et al., Drug Development Research, 2004; 61(3): 108-120). Achieving the high protein concentration necessary for subcutaneous delivery can be problematic due to protein aggregation. Aggregation is the result of intermolecular interactions and, thus, is enhanced by high protein concentrations. The presence of protein aggregates in an injected solution, even in small doses, poses a threat of an immune response that can reduce the efficacy of the protein over time and, more importantly, has the potential to elicit adverse reactions (Frokjaer, S. et al., Nature Reviews Drug Discovery, 2005; 4(4): 298-306; Wang, W., et al., International Journal of Pharmaceutics, 2005; 289: 1-30; Manning, M. C., et al., Pharmaceutical Research, 2010; 27(4): 544-575; Cromwell, M. E. M., et al., 2006; Rosenberg, A. S., AAPS J., 2006; 8(3): E501-E507).